Remote control system



A. R. HOPKINS 1,999,359

REMOTE CONTROL SYSTEM April 30, 1935.

Filed Aug. 20, 1951 TUNlNG BDNTROLS H I NV EN TOR.

Alva RHopKins,

ATTORNEY.

Patented Apr. 30, 1935 UNITED STATES {PATENT OFFICE REMOTE CONTROL SYSTEM Alva R. Hopkins, Merchantville, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application August 20,

14 Claims.

, other similar apparatus whereby their various functions may remotely be controlled. More particularly, it relates to a system for remotely operating the tuning and volume, or other major control elements, of radio apparatus.

In control systems of this character, for radio receiving apparatus and the'like, it is common practice to provide electric motor means for operating the tuning control element and to extend the motor circuits to the desired remote control points. Other major control elements of the apparatus such as the volume control, for example, are usually located at the remote control point and the apparatus circuits are extended directly thereto. In certain instances, additional motor means are provided for the control of such elements, and the circuits for the second motor means are extended in the same manner as those for the tuning control motor means.

The extension of the apparatus circuits has certain inherent and well recognized disadvantages involving, among other things, the liability of undesired coupling between certain of the leads of the extended circuits and the exposure of such leads to interference from external sources. The use of an additional motor for each additional major control element to be remotely operated involves additional cost and complication, as well as space in the apparatus, and additional control wires between the apparatus and the remote control point.

Accordingly, it is an object of the present invention to provide an improved and simplified radio control system which combines two remote control functions of the above referred .to character, in a single motor means and circuit therefor, thereby reducing in number the extended control circuits, obviating the necessity for extending the apparatus circuits to the remote point and the'use of additional motor control means.

By way of example, in accordance with the invention, there may be provided a single electric motor means for. operating both the tuning and volume control elements of a radio receiving apparatus, directly mounted uponthe apparatus, whereby the circuits of the apparatus are not disturbed or extended. Furthermore, a single remote control circuit connected with the motor may be arranged for both the tuning and volume control operation of the motor selectively at a remote control point, thereby simplifying the remote control circuit and facilitating its extension to other remote control points.

1931, Serial No. 558,202

The invention will, however, be better under stood from the following description, when taken in conection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the drawing, Fig. 1 is a view in perspective of control apparatus embodying the invention in connection with the tuning and volumecontrol elements of a radio receiving apparatus; Fig.2 is a wiring diagram of the control circuits for the 10 apparatus shown in Fig. 1; and Fig. 3 is a wiring diagram showing a modification of a portion of the circuit of Fig. 2.

Referring to Fig. 1, the tuning and volume control means or elements of a radio apparatus such as areceiver are represented respectively by a variable gang tuning condenser 5 and a variable resistor or potentiometer 6 mounted upon the frame or chassis 'l forming part of the apparatus.

The tuning and volume control elements are provided with control shafts 8 and 9, respectively, which shafts are connected with suitable reduction gearing means such as that indicated at 10 and H, whereby they may be driven or controlled at desired rates of speed by an electric motor l3.

The motor is mounted adjacent to the shafts to be controlled and, in the present example, between two spaced bracket members l4 and I 5 that support the reduction gearing units l0 and H. This provides a compact arrangement of parts on the chassis. The motor is secured to the bracket l4, while the volume control means 6 is mounted on the bracket l5 in substantially the same relative position as the motor on the bracket H, with its shaft in direct connection with the gearing Ii thereon. The control shaft 8 for the tuning means is extended to the gearing [0 through the brackets which provide journal bearings lS- -IB for the extension.

The motor is arranged to be connected with and to operate selectively the one or the other of the control shafts in response to the value of the operating potential applied to it. In the present embodiment of the invention, the motor shaft is 5 provided with end play, whereby it is movable axially to establish the desired connection under control of certain applied potentials for the motor. A pair of pinions l8 and IS on opposite ends of the motor shaft are so arranged in relation to the gearings l0 and II, which are aligned to engage with them, that they may selectively engage with the one or the other of said gearings as the motor shaft is moved axially between its limits of travel.

The motor shaft is biased to move axially to an extended or displaced position as one limit of its travel substantially as shown by a suitable spring 20, which is arranged to engage one end of the shaft. In this position, the pinion l9 engages with the gearing H to provide a driving connection between the motor and the volume control element 6 and its control shaft 9. The spring is of suflicient strength to hold the shaft normally in the position shown and in gear with the volume control means, while the motor is energized at a certain lower than normal potential to operate the volume control element.

When a certain higher potential, such as the normal operating potential, is applied to the motor, the shaft I1 is caused to move axially, overcoming the spring pressure, and thereby disengaging from the volume control gearing and engaging with the tuning control gearing. In the present example, this is effected by the end thrust or pull of the field on the armature. The motor has a greater torque under this condition of operation and operates at a higher speed to drive the tuning control means.

The spring 20 at the end of the shaft causes it to be returned to its displaced position and connected with the volume control means when the motor is de-energized. With a reversible motor, this action takes place in either direction of operation; therefore, controlling the potential applied to the motor determines its function.

Advantage may also be taken of the shifting action of the driving means to actuate switching means or one or more circuit controlling elements. In the present example, switching means is provided in connection with the leaf spring 20. The latter is mounted on the base I by means of a bracket 2| which carries an insulating block 22, on which is mounted a switch comprising two sets of contacts 23 and 24. Two of the contact carrying members 25 of the switch are connected by an operating rod 26 to the spring 20, whereby the switch contacts are closed when the motor shaft shifts to the driving position for operating the tuning control shaft 8. In other embodiments of the invention, other switch ng means may be provided in connection with the driving means, whereby movement of an element of the latter for changing the driving connection may operate a circuit controlling element.

It will be noted that, in the foregoing control arrangement, a common motor is employed to operate, selectively, two different control shafts. Furthermore, the motor, the gearing, and the control shafts are arranged for compact mounting, and the elements controlled by the motor are located directly on the apparatus chassis, whereby the control leads thereto may be made in the usual manner.-

It will be seen that, by applying different voltages to the common motor, either the tuning control element or the volume control element of the apparatus may, selectively, be controlled, In the present example, this is provided by permitting the motor armature and driving shaft to have suflicient end play to carry the pinion gears into mesh with either one of the sets of gearing. It is obvious, however, as above noted, that other control means may be provided in which the connection may be changed in response to the operating potentials applied to the motor.

From a consideration of the foregoing description, it will be appreciated that the selective control of the tuning and volume control elements of a radio apparatus may be effected at a remote motor, is employed to point through a single circuit for energizing the motor, by applying the selected potentials to the circuit at the remote point. The application of a remote control circuit of the above character in connection with the apparatus in Fig. 1 and as applied to a radio receiver is shown in Fig. 2, to which, more particularly, attention is now directed.

In Fig. 2, in which the same reference numerals are employed for like parts as in Fig. 1, it will be noted that the volume control element 6 is connected as a potentiometer in the input circuit 21 of a radio receiving apparatus and that the tuning control element 5 is connected in the usual manner in the tuned circuits indicated at 28 and 29 in connection amplifier 30, and a detector 3|. The detector is connected by a suitable audio transformer 32 to an audio amplifier 33 which supplies a loud speaker 34 through a suitable output transformer 35.

The tuning and volume control elements are connected with the motor l3 through shafts indicated at 8 and 9 and through their respective gearing units l0 and II. The motor armature is indicated at 36 and it will be noted that it is in slightly displaced relation to the energizing or field windings 37, being held in this position by the spring 20 bearing against the end of the shaft H. The pinion I9 is thereby engaged with the gear train I I, completing a driving connection with the volume control 6.

Operating current is supplied to the motor through a suitable step-down transformer 38 from supply leads indicated at 39. In the apparatus of the present example, the transformer is designed to step-down the usual H0 volts supply potential to a normal operating potential for the motor of 23 volts. This is applied to the motor through a common circuit lead 40 connected between one terminal of the secondary of the transformer and a common supply lead 4| for both field or energizing windings of the motor.

The opposite side of the secondary of transformer 38 is connected to a remote control lead 62 which is extended through a suitable cable connection indicated at 43, to a remote control station 44 and is connected to one terminal each of a series of selector switching means 45.

Two of the switching means, indicated in the drawing as Tuning controls, are provided with direct return lead connections 46 to the motor control windings 31. In the present example, these are reversing windings and when energize by closure of the one or the other of the tuning control selector switches, cause the motor to operate in the one or the other direction at normal speed. An inductor and capacitor circuit indicated at 4! in connection with leads 48 at the assist the operation of the motor in either direction.

The circuit for energizing the motor through the remote tuning control switching means may be traced from the secondary of the transformer 38 through the lead 42, thence through the selected one of the tuning control selector switches and its corresponding lead 46 and energizing winding 31, back to the transformer secondary through the lead 40. Thus, to operate the motor from a remote point in one direction or the other, a single remote control circuit is necessary.

Since the normal operating potential is applied to the motor by the tuning control selector switches, the motor armature 38 will be retracted to its normal operating position and will drive with a radio frequency the tuning control means .5 through gearing l0 and shaft 8 as hereinbefore described. 7

To enable operation of the volume control means 5 through the same circuit, a resistor 48 is connected between each of the leads 48 and the common remote control lead 42 by other switching means indicated as Volume controls".

In the present example, the resistors 48 are of approximately 60 ohms in value, which is sufficient to lower the operating potential applied to the motor from 23 to Hi volts. The last named potential, when-applied to the motor by closure of either one of the volume control selector switches causes the motor to operate with sumcient torque to drive the volume control means through the gearing H and shaft 9. It does not, however, apply sufficient end thrust to the armature to overcome the holding action of the spring 28, whereby the pinion l9 remains in mesh with the gearing H.

By this circuit arrangement, wherein the same remote control circuit is used for both the tuning and the volume control operation, the number of leads required in the cable 43 may be reduced to two or even one if a ground return is used. Thus, for operation of the tuning and volume controls in both directions as in the present example, only three leads are required between the remote control unit 44 and the apparatus associated with the receiver.

Current is also supplied to the receiving apparatus through a suitable power transformer indicated at 49 from the supply leads 39. A relay control switch 49' having a closing coil 50 and an opening coil 5| may be utilized to control the power to the receiving apparatus.

In the present example, both coils are connected with the transformer 38 and receive operating current therefrom through suitable switching means. The closing coil 50 is connected with the transformer 38 through leads 52 and 53, the latter lead including in series therewith one pair of contacts 23 of the switching means-connected with the spring 26, while the opening coil is connected with the transformer 38 through the lead 52 and a remote control lead 54, which is extended to one of the switching means 45 included in the remote control unit 44, and indicated as the Off selector switch. The return to the transformer is completed through this switch and the common return lead 42.

' when the tuning control means is With this arrangement, it will be seen that actuated by operation of either of the tuning control selector switches, the contacts 23 will be closed, whereby the closing coil 50 will be energized to close the switch 49 and thereby to energize the receiving apparatus through the transformer 49. The receiving apparatus may be de-energized by operation of the Off selector switch which energizes the opening coil of the relay and causes the switch 49' to open. In an arrangement of this character, the transformer 38 is at all times connected with the supply leads 39 and is energized in readiness to supply the motor and the coils of the switch 49'.

It will also be seen that, by the addition of a single wire or lead 54 to the cable 43, the control of the power for the apparatus is also extended to the remote control station 44 without including the higher potential leads of the power supply circuit in the cable.

As an example of the further use of the circuit controlling means or switching means, arranged to be actuated by the shifting connection between the driving motor and the shafts controlled thereby, the contacts 24 of the switching means of the present example are connected by leads indicated at 55 with a circuit of the apparatus, such as the secondary circuit of transformer 32, to control the circuit, thereby to suppress the volume of output from the loudspeaker 34 during the tuning operation In the present example, the volume is reduced to the desired degree by placing a resistor 56 in parallel with said secondary, through the circuit leads 55 and the switch contacts 24. As indicated, the resistor is variable, whereby the desired degree of suppression of the volume may be obtained during the tuning operation.

Referring now to Fig. 3 in which the remote control station 44 is indicated, it will be noted that the coils 51, of a relay 58, are included in circuit with the volume control selector switches in lieu of the resistors 48 of Fig. 2, whereby in addition to providing the necessary potential drop for operation of the motor, in connection with the volume control element, the relay may be utilized to control, by operation of its contacts 59, other circuits such as a circuit 5|), in response to the operation of the volume control selector switches. From the foregoing description, it will be seen that a radio control system embodying the invention has, among other things, the following advantages:

One motor is employed for both the tuning and volume control means and may selectively be operated to effect the tuning and volume control operations for the apparatus through the same circuit.

Tuning and volume control selectively and in both directions is permitted while utilizing but three extension leads in the remote control circuit.

The tuning and volume control elements are permitted to be located directly within the apparatus to be controlled, thereby obviating the necessity for extending the apparatus circuits to the remote point.

The means employed for changing the driving connection automatically in response to the potentials applied to the driving motor may readily be adapted for operating circuit controlling devices connected in the apparatus circuits, adapted to simplify and improve the operation of the apparatus.

Because of the simple remote control circuit, the latter may easily be extended to additional control stations by a minimum number of extension leads.

While the invention has been illustrated and described in connection with a radio receiving apparatus, it should be understood that it is not limited thereto and that it may be applied to other apparatus having a plurality of control shafts adapted to be remotely controlled.

I claim as my invention:

1. In combination, a plurality of movable control devices, a single electric motor means having an element selectively responsive to differing applied operating potentials for moving selectively into driving connection with each of said devices, and means for selectively applying said differing operating potentials to said motor means.

2. In radio apparatus having a plurality of movable control devices and a control shaft for tentials to said second named means selectively,said last named means including a single electric motor means having a driving element movable to operate selectively in mechanical connection with said first and second named means in response to differing operating potentials applied to the motor.

4. The combination with radio apparatus having tuning control means and volume control means, of means for remotely controlling said first and second named means selectively, said last named means including a single electric motor means having a driving element movable to operate selectively in mechanical connection with said first and second named means in response to differing operating potentials applied to the motor, and means for selectively applying said differing operating potentials thereto.

5. The combination with radio apparatus having tuning and volume control elements, of a single electric driving motor mechanically connected with one of said elements to operate it, a motor control circuit, means connected with said circuit for energizing the motor selectively at differing operating potentials, and said motor having movable means responsive to one of said potentials for changing said operating connection with the one of said control elements to the other of said control elements to operate the latter.

6. The combination with radio apparatus having tuning and volume control shafts, of an electric motor, means providing a releasable mechanical driving connection between the motor and one of said shafts, means including a movable element responsive to current fiow to the motor for releasing said connection and completing a mechanical driving connection between the motor and the other of said shafts, said last named means being adapted to be electrically actuated when said motor is energized at a predetermined operating potential, and means for selectively energizing the motor at said operating potential and a second predetermined operating potential for driving said one shaft through said first connection.

7. The combination with radio apparatus having tuning and volume control shafts, of an electric motor, means providing a releasable mechanical driving connection between the motor and one of said shafts, means including a movable element responsive to current flow to the motor for releasing said connection and completing a mechanical driving connection between the motor and the other of said shafts, said last named means being adapted to be electrically actuated when said motor is energized at a predetermined operating potential, a single circuit through which said motor is energized, and switching means connected with said circuit for selectively applying said operating potential and a second operating potential to said circuit for driving said one shaft through said first connection. 7

8. In a remote control system for radio receiving apparatus, the combination with a pair of control shafts, of a gearing connected with each of said shafts, an electric motor having an axially movable shaft, means carried by said shaft for engaging the one or the other of said gearings when said shaft is moved axially to the one or the other of predetermined limits of travel, spring means connected with said shaft to move it to one of said limits, means responsive to an operating potential applied to the motor for moving said limits, and means named means in response to differing operating potentials applied to the motor, a single circuit for supplying operating potentials to said motor, and switching means connected with and directly actuated by said motor for controlling the apparatus when said motor is connected with said tuning control means.

10. The combination with a radio receiving apparatus having a tuning control shaft and a volume control shaft, of an electric motor, means providing a driving connection between said motor and each of said shafts, means for selectively changing said connection with the motor from one shaft to the other, switching means responsive to the operation of said last named means, a remote control circuit for the motor, a switch in said circuit and a second switch and a resistor in series therewith in said circuit in parallel with the first named switch for controlling said motor.

11. In radio apparatus, the combination with tuning and volume control devices therefor, of a motor shaft, said shaft being axially movable to establish a driving connection selectively with either of said devices, means for moving said shaft in a direction to provide a driving connection with one device. and means for applying an operating potential to the motor for causing said shaft to move in a direction to provide a driving connection with the other device, said driving connection including a gearing connected with each of said devices and a pinion on the motor shaft for selectively engaging said gearings.

12. In a radio apparatus, the combination with a base, and tuning and volume control devices thereon for said apparatus, of an electric motor having an axially movable drive shaft and pinion means thereon, a reduction gearing for the tuning control device and a reduction gearing for the volume control device adapted to provide driving connections between said motor and said devices, a supporting bracket for the motor and the first named gearing, a second supporting bracket for the volume control device and the second named gearing, said volume control device and second named gearing being directly connected, said brackets being mounted on the base in spaced relation to each other to receive the motor between them, means for moving said motor shaft to establish a driving connection between said pinion means and one of said gearings, means for applying a higher and a lower operating potential to the motor, said motor being responsive to the higher potential to cause said shaft to move in a direction to open said driving connection and to establish a driving connection between said pinion means and the other of said gearings, and a single circuit connection between said last named means and the motor.

13. In a radio apparatus, the combination with (iii tuning and volume control devices therefor, of an electric motor having an axially movable drive shaft and pinion means thereon, a reduction gearing for the tuning control device and a reduction gearing for the volume control device adapted to provide driving connections between said motor and said devices, said volume control device and second named gearing being directly connected, means for moving said motor shaft to establish a driving connection between said pinion means and one of said gearings, means for applying a higher and a lower operating potential to the motor, said motor being responsive to the higher potential to cause said shaft to move in a direction to open said driving connection and to establish a driving connection between said pinion means and the other of said gearings, and a single circuit connection between said last named means and the motor.

14. In radio apparatus, the combination with tuning and volume control devices therefor, of a motor shaft, said shaft being axially movable to establish a driving connection selectively with either of said devices, means for moving said shaft in a direction to provide a driving connection with one device, means for applying an operating potential to the motor for causing said shaft to move in a direction to provide a driving connection with the other device, a control circuit for said apparatus, and a switch in said circuit associated with said shaft to be actuated by axial movement thereof.

In testimony whereof, I have hereunto subscribed my name this 12th day of August 1931.

ALVA R. HOPKINS. 

